Tag: mix and separate

Questions Related to mix and separate

When $1$ mole of a substance is present in $1$ L of the solution, it is known as :

  1. normal solution

  2. molar solution

  3. molal solution

  4. None of the above


Correct Option: B
Explanation:

Molar concentration is a measure of the concentration of a solute in a solution and its unit is mol L$^{-1}$. Molarity is a method to express the concentration of a solution. It is defined as the number of moles of solute dissolved per liter of solution. 


Hence, when $1$ mole of a substance is present in $1$ L of the solution, it is known as a molar solution.

Option B is correct.

A solution in which, still more number of solute can be dissolved, is known as :

  1. unsaturated

  2. super saturated

  3. saturated

  4. dilute

  5. concentrated


Correct Option: A
Explanation:

Saturated Solution: A solution with a solute that dissolves until it is unable to dissolve any more, leaving the undissolved substances at the bottom.


Unsaturated Solution: A solution (with less solute than the saturated solution) that completely dissolves,  in which still more solute can be dissolved.


Supersaturated solution: Solution that is more concentrated than a saturated solution is known as a supersaturated solution. If a crystal of solute is added to this solution, the excess of solute crystallizes.

A dilute solution: is one in which there is a relatively small amount of solute dissolved in the solution.

A concentrated solution: contains a relatively large amount of solute dissolved in the solution.


Hence option A is correct.

10g of sodium hydroxide dissolved in 1 L of water to make _____ solution.

  1. $0.25 M$

  2. $0.5 M$

  3. $1 M$

  4. $1.5 M$

  5. $4 M$


Correct Option: A
Explanation:
molar mass of sodium hydroxide $=$$40g/mole$
$Molarity = \dfrac{Mass\, of\, solute}{(Molar\, mass\, of\, the\, solute)\times(Volume\, of \, solution\, in\, litres)}$

So $Molarity$ $=$$10/(40\times1)$$=$$0.25M$

Which of the following sequences lists the relative sizes of particles in a water mixture from smallest to largest?

  1. Solutions, suspensions, colloids

  2. Solutions, colloids, suspensions

  3. Colloids, solutions, suspensions

  4. Colloids, suspensions, solutions

  5. Suspensions, colloids, solutions


Correct Option: B
Explanation:
The sequence that gives the relative sizes of particles in a water mixture from smallest to largest is solutions, colloids, suspensions. In true solution, the particle size is 0.1 nm to 1.0 nm. In colloidal solution, the particle size is 1 nm to 1000 nm. In suspension, the particle size is more than 1000 nm.

How much water, in liters, must be added to 0.5 L of 6 M HCl to make it 2 M?

  1. 0.33

  2. 0.5

  3. 1

  4. 1.5

  5. 2


Correct Option: C
Explanation:
Molarity =$\dfrac{Mass \,of\, the\, solute}{(Molar \,mass\, of\, the\, solute)\times {(Vol. of\, soln.\, in\, liters)}}$

Mass of solute will remain same before and after mixing water.
so 
       $M _1V _1$$=$$M _2V _2$
or 
       $V _2$$=$$6\times0.5/2$$=$$1.5L$
this is final total volume so water added $=$$1.5-0.5$$=$$1L$ 

What is the molar mass of a non-ionizing solid if 10 g of this solid, dissolved in 100 g of water, formed a solution that froze at $-1.21^o C$?

  1. 0.65 g

  2. 65 g

  3. 130 g

  4. 154 g

  5. 265 g


Correct Option: D

Which of the following is not miscible in alcohol?

  1. Water

  2. Petrol

  3. Diesel

  4. Kerosene


Correct Option: B,C,D
Explanation:

Water is miscible in alcohol due to hydrogen bonding between the hydrogen and oxygen atoms. Since petrol, diesel and kerosene are non-polar in nature, they are insoluble in alcohol which is a polar solvent.

Hydrogen gas adsorbed on surface of platinum is an example of solid in gas solution.

  1. True

  2. False


Correct Option: A
Explanation:

Platinum is present in solid state and when hydrogen gas is adsorbed on the surface of platinum then they are forming solid in gas solution because soild is very  small and is present as solute and the amount of gas adsorbed is much more then platinum so it act as solvent and complete solution is known as solid in gas.

Sugar is soluble in water due to:

  1. high solvation energy.

  2. ionic character of sugar.

  3. high dipole moment of water.

  4. hydrogen bond formation with water.


Correct Option: D
Explanation:

 The bond between the oxygen and hydrogen atoms ($O–H$ bond) in sugar (sucrose) gives the oxygen a slight negative charge and the hydrogen a slight positive charge.Sucrose is a polar molecule.

Which of the following is a true solution?

  1. $NaCl$ is sulphur dioxide

  2. Copper in silver

  3. Salt in petrol

  4. Mud in water


Correct Option: B
Explanation:

NaCl in sulphur dioxide from molten sodium sulfate. Copper and silver are melted together to forms an alloy, salt is insoluble in petrol because petrol is non-polar solvent. Mud in water forms a colloidal solution, so, from the given options Copper in silver forms a true solution.